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Thread: vm33"s

  1. #1
    Hooligan
    Join Date
    Jan 2007
    Location
    Ont.,Can.

    vm33"s

    anyone have any luck getting the bog at wot below 4500 rpm out of these carbs?what carbs r u guys using?
    76kZ . gusset work,1200CC.Mukini RS34"s.,ported by Larry Cavanough Racing,1.5mm.over intakes,.424" lift cams,under bucket shims,pods,Kerker, undercut trany,Billet 2nd, Earl cooler,Dyna 2000 with 2.2 ohm coils,05 ZRX12 rear end and seat.ZX9 front end.
    01cbr6 track bike
    Cobourg,Ont.,Canada.

  2. #2
    Sybil Servant
    Join Date
    Jul 2006
    Location
    Northern VA

    Re: vm33"s

    Originally posted by mark1135cc
    anyone have any luck getting the bog at wot below 4500 rpm out of these carbs?what carbs r u guys using?
    I don't have any bog at any RPM.

    I am using stock carbs. They work quite well for 99% of us. For a select few with major engine modifications, there are some racing-only carbs you could use. Generally, racing carbs only work well at WOT and are not happy on the street.

    What mods have been done to your bike? Your profile says you don't have a ZRX or any mods.

    If it is stock, your AirBox lid is probably not in place correctly, leaving it open at the bottom causing the bike to run badly.

    If you have installed a full exhaust system, you need to re-jet the carbs to deal with the new flow. Otherwise, it will not run well.

    Without more information, we can't help much. I can say though, there is no flat spot or bog or hesitation with my bike at any RPM.
    I am the voice of Unreasonbl.

  3. #3
    Hooligan
    Join Date
    Jan 2007
    Location
    Ont.,Can.
    Thanks .i updated my sig.
    it seems that most guys use the legendaryvm29mm. smoothbores.this gives them more tuning ability but the performance is only a little better than the stock 28"s.
    some use a cv type 34 (bs34) off the police and other bikes and these are reported to be just slightly better than stock as well.
    then comes the vm33"s,these are reported to bee a bigg step up above 4500 rpm and cruise nice (i can atest to this) but they suffer from a bog if u snap the throttle wide open fast below 4500 rpm.
    i have had some mixed reviews on the rs34"s some say there great ,some say they lact power below 4000 and work well above 4000.
    i have not heard enough about the cr"s and fcr"s yet to coment but some like them.

    the problem seems to be the velocity drops too much with the big carbs and if u go wot bellow 4500 rpm they cannt pull enough fuel out and it goes lean till u get above 5000 rpm.some report that the problem gets better if u go to a 1200cc motor.
    so i am trying to tune mine the best i can and would like to hear from anyone who has any tips for me.
    yesterday i raised the needle from #3 to 4 and the bog was slightly better but the cruiseing was rich so i opened the pilot screws till it felt better .i was surprised how much diff 1 clip change made.i was on the lean side on all circuts and it went way rich.
    76kZ . gusset work,1200CC.Mukini RS34"s.,ported by Larry Cavanough Racing,1.5mm.over intakes,.424" lift cams,under bucket shims,pods,Kerker, undercut trany,Billet 2nd, Earl cooler,Dyna 2000 with 2.2 ohm coils,05 ZRX12 rear end and seat.ZX9 front end.
    01cbr6 track bike
    Cobourg,Ont.,Canada.

  4. #4
    Sybil Servant
    Join Date
    Jul 2006
    Location
    Northern VA
    Originally posted by mark1135cc
    Thanks .i updated my sig.
    it seems that most guys use the legendaryvm29mm. smoothbores.this gives them more tuning ability but the performance is only a little better than the stock 28"s.
    some use a cv type 34 (bs34) off the police and other bikes and these are reported to be just slightly better than stock as well.
    then comes the vm33"s,these are reported to bee a bigg step up above 4500 rpm and cruise nice (i can atest to this) but they suffer from a bog if u snap the throttle wide open fast below 4500 rpm.
    i have had some mixed reviews on the rs34"s some say there great ,some say they lact power below 4000 and work well above 4000.
    i have not heard enough about the cr"s and fcr"s yet to coment but some like them.

    the problem seems to be the velocity drops too much with the big carbs and if u go wot bellow 4500 rpm they cannt pull enough fuel out and it goes lean till u get above 5000 rpm.some report that the problem gets better if u go to a 1200cc motor.
    so i am trying to tune mine the best i can and would like to hear from anyone who has any tips for me.
    yesterday i raised the needle from #3 to 4 and the bog was slightly better but the cruiseing was rich so i opened the pilot screws till it felt better .i was surprised how much diff 1 clip change made.i was on the lean side on all circuts and it went way rich.
    Post up more information about the current breathing status ...

    Jetting
    Pods/Airbox
    exhaust
    cams
    engine mods
    etc.
    I am the voice of Unreasonbl.

  5. #5
    Savannah Six charter member
    Join Date
    Mar 2004
    Location
    Middle of town in the middle of Ct

    J

    KZ motor


    There comes a point in your life when you realize. Who matters.Who never did.Who won't anymore.And who always will.So,don't worry about people from your past.There's a reason why they didn't make it to your future.
    March 2015 BOTM
    2015 BOTY

  6. #6
    Sybil Servant
    Join Date
    Jul 2006
    Location
    Northern VA

    Re: J

    Originally posted by EL'zREX
    KZ motor
    I am the voice of Unreasonbl.

  7. #7
    Hooligan
    Join Date
    Jan 2007
    Location
    Ont.,Can.
    well the problem is the bog below 4500 rpm @wot.
    it runs veeery strong above 5000 to red line .it will cruise nicely,u would never know these were not perfect carbs if u didnt go wot below 4500rpm.if i go 3/4 throttle its pritty good but wot makes it fall on its face.im still playing with the jetting. i moved the needle to #4 from #3 yesterday and it seemed to help a bit but it made it way rich at cruise so im opening the pilot screws and tring to find a spot were it will run better.will try again today.im thinking i should try a richer (thinner) needle.it has o-8"s .(mikuni manual say try p-2"s with a kerker and .06 main air jets instead of 1.0"s)i have 1.2 main air jets now but just bought some .06"s to try next. im wondering if a stock baffle would help this? i hav a home made 2 " perferated baffle that goes in just past the bend in the slip on tail.
    i should mention that everyone seems to think this is a lean condition but why would it be worse at wot than 3/4 throttle?? also the otherday i checked all throttle positions and the plugs were white(needle was at #3 then).then i ran it through the bog zone several times and the plugs went black.when i replaced the plug and went wot above the bog zone 5000 to red line several times ,this cleaned the plugs up?sound like its rich in the bog zone??
    is that enogh info.lol
    76kZ . gusset work,1200CC.Mukini RS34"s.,ported by Larry Cavanough Racing,1.5mm.over intakes,.424" lift cams,under bucket shims,pods,Kerker, undercut trany,Billet 2nd, Earl cooler,Dyna 2000 with 2.2 ohm coils,05 ZRX12 rear end and seat.ZX9 front end.
    01cbr6 track bike
    Cobourg,Ont.,Canada.

  8. #8
    BadAss Hooligan
    Join Date
    Nov 2002
    Location
    Hayesville, ohio
    I had a set on an 1105 motor and hated them,I went to the rs34mm and love em-Jesse
    '99ZRX 1100 (muzzy,zx-11 cams,FCR's)
    '04Kawasaki V-Force(It's fast)
    '96Harley BadBoy(sled)
    '88 Kawasaki Tecate 4

  9. #9
    Hooligan
    Join Date
    Jan 2007
    Location
    Ont.,Can.
    jesse did u find a lack of bottom end?i would like to here how they felt at all rpms,were there any flaws at all?its hard to find any one that has actualy used them.most of the guys use 36's and complain of no low end below 4000rpm.just what all the details befor i deside to get some.Thanks.
    76kZ . gusset work,1200CC.Mukini RS34"s.,ported by Larry Cavanough Racing,1.5mm.over intakes,.424" lift cams,under bucket shims,pods,Kerker, undercut trany,Billet 2nd, Earl cooler,Dyna 2000 with 2.2 ohm coils,05 ZRX12 rear end and seat.ZX9 front end.
    01cbr6 track bike
    Cobourg,Ont.,Canada.

  10. #10
    BadAss Hooligan
    Join Date
    Nov 2002
    Location
    Hayesville, ohio
    I really didnt notice any lack of bottom end power,but my bike is geared very low(5200rpms at 60 mph) it is great around town.They do rattle like hell and that bothers some people but not me.
    '99ZRX 1100 (muzzy,zx-11 cams,FCR's)
    '04Kawasaki V-Force(It's fast)
    '96Harley BadBoy(sled)
    '88 Kawasaki Tecate 4

  11. #11
    Appalachian American
    Join Date
    Sep 2001
    Location
    Alabama
    When you get the CV34's, what do ya want for the rack of VM's? The 400 could use a couple
    The older I get, the faster I was
    '99 ZRX 1100
    '78 KZ400 B1 Bike of the Month
    July 2007 KZ Rider.com
    '05 Chinese Fiddy

    We will not allow one of our legends nor his family to suffer in silence or alone.The rally cry has been given, we stand fast to do that which is required of us; say but the word and we will be there for our comrade.

    --C. Nafziger

  12. #12
    Hooligan
    Join Date
    Apr 2002
    Location
    Upstate NY

    Re: vm33"s

    Old thread, I know...

    I have VM33 carbs on a bike Iím starting to revive. I just wanted to say that, before electrical and medical issues got in the way, these carbs were very dialed-in for my purposes, which was (fast) street use, on an Ď83 GS1100ES.

    I wish I knew the settings on them, but I didnít build it. I might soon enough, though, if seafoam doesnít bring them back to life after a stator/RR replacement.

    The carbs did exactly what the brochure claimed, very easy to control on the street, but huge top end. I donít remember any lag or flat spots, etc. I know Iím lacking specifics here, but just wanted to encourage folks that these can be very well tuned carbs. Probably the best tuned carbs Iíve had on any bike, including some RS flats.

    I am tempted at times to move these to my Ď99 ZRX, but lots of other projects first.
    fastfrank

    Ď78 KZ750 twin
    Ď83 GS1100ES
    Ď99 ZRX1100 : Green, CVK40 carbs, ZX11 cams, ZX11 wheels, +4 advancer, Supertrapp tunable full system
    Ď11 GW250

  13. #13
    Hooligan
    Join Date
    Apr 2002
    Location
    Upstate NY

    Re: vm33"s

    Well, my VM33 carbs have seen better days... managed to get them off today (hardest part was getting the lower throttle cable loose) and took off the caps and float bowls, and two of the four are in need of more work (#1,#2), and the throttle shaft is frozen. Been sitting way too long, but there are signs these two were having issues before it sat.

    These seem pretty easy to work on, and I like how you can access main jets through the bottom plugs. #2 was pretty gunked up, cleaned out the main jet, and got some penetrating oil on the throttle shaft to sit overnight, but the two floats donít move right. I need to a proper manual on these.

    On a positive note, carbs #3 and #4 actually look pretty great. Iím guessing that 1,2 werenít getting adequate vacuum for awhile (while the bike was loaned out - heíd said it was running rough).

    Well, its progress.
    fastfrank

    Ď78 KZ750 twin
    Ď83 GS1100ES
    Ď99 ZRX1100 : Green, CVK40 carbs, ZX11 cams, ZX11 wheels, +4 advancer, Supertrapp tunable full system
    Ď11 GW250


 

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